I don't reboot the emulator. I use Eclipse and push Ctrl+F11 with a running emulator.

During development phase, it is waste of time. I usually write a few lines of code and then check the result very frequently. If it were just java program, it would take 2~3 second to see what I have changed.

Is there any way to make it faster? I haven't tested it on phone, because I don't have one. Developing with a phone takes shorter time for development?

Depends on your PC specification, we have an old PC that it is quicker to deploy to a phone connected via USB than it is to deploy to the emulator. We also have a current high spec PC that loads emulator app's pretty fast.